1. Field of the Invention
The present invention relates generally to mechanized transport devices for heavy loads, such as containers and molds, and, more particularly, to device for lifting moving, inverting and releasing such heavy loads. Specifically, the present invention relates to devices for lifting and moving heavy containers such as molds used in the manufacture of concrete articles.
2. Description of the Prior Art
There are a wide variety of different types of devices designed to lift and carry materials and containers ranging from forklift trucks and overhead hoist systems used in factories, and the like, and container carrying trucks of various types. There are a number of existing vehicle designs which include mechanisms for lifting and then rotating containers in order to deposit or to discharge the contents therefrom. Examples of such devices include U.S. Pat. Nos. 3,291,329; 3,917,093; 3,330,429; 3,335,885; 3,520,429; 3,863,791; 4,027,808; 4,168,930 and 4,624,618. In each of these prior art examples, either the containers are intricately associated with the transport vehicle, which in most instances is a truck, or the container is lifted by the vehicle, moved to a discharge station and then tipped to discharge materials from the container. However, in each instance the container is then returned to its upright position, and unless it is permanently associated with the vehicle, then returned and deposited to their original upright position. In no such prior art is the container known to be inverted 180.degree. or more, nor is the container deposited and released in an inverted position inasmuch as such an arrangement would be incompatible with the function of these devices.
The manufacturer of concrete articles, such as cisterns, concrete building blocks, and the like, generally includes the use of various molds for forming the concrete article.
Lifting and movement of such concrete molds requires specialized equipment as disclosed by way of example in U.S. Pat. Nos. 1,920,716; 3,868,025 and 5,511,927. The molds disclosed in these particular references, however, do not require inversion during the process of lifting and moving them and/or their concrete components. Inasmuch as such molds and concrete articles in them weigh substantial amounts, the mere lifting and moving of these molds and concrete components is very difficult, and inversion of such molds is not taught or even suggested. A known device marketed as the Posi-Turner manufactured by Elk River Concrete Products, Shakopee, Minn., illustrates an arrangement that is specifically designed to invert a mold once the concrete has been poured and cured therein. However, this particular arrangement necessitates the permanent attachment of the mold to the Posi-Turner carrier device which moves the mold and rotates it. Thus, only one mold per carrier device can be utilized in this prior art system, thereby either limiting production or requiring a plurality of such devices.
Therefor, there is a need for a device which is adapted to lift and move heavy loads, including concrete mold containers, which device is also capable of inverting these loads and releasing them in an inverted position. It is also desirable to have such a device which has the capability of releasing such loads or molds, with the result that it can handle multiple loads in order to increase the efficiency of use of such a device.